I failed emissions!!! :(

the most likely problem is that you have a bad 02 sensor or sensors. however you problem could also be
-timing
-bad cats
-bad coil pack(s)
-bad plugs
-dirty throttle body
-bad injector / dirty etc
amoung other things

my point is everyone here is guessing. if you want to fix this with oem parts even the o2 sensors are relatively expensive, however after market ones are cheap enought that it *might* be worth trying to swap them to see if that fixes the problem.. but realize that you are guessing. and could likely be guessing wrong and wasting time and money. If i were you i would take the car to a different qualified mechanic who can diagnose the car and not simply guess and swap parts.

if you had a trouble code (CEL) then we could help you by determining the likely cause behind the cel code number, but i have not seen that, so i think the reasonable thing to do is take the car to a qualified shop to diagnose and fix the problem.
 
socalx said:
the most likely problem is that you have a bad 02 sensor or sensors. however you problem could also be
-timing
-bad cats
-bad coil pack(s)
-bad plugs
-dirty throttle body
-bad injector / dirty etc
amoung other things

my point is everyone here is guessing. if you want to fix this with oem parts even the o2 sensors are relatively expensive, however after market ones are cheap enought that it *might* be worth trying to swap them to see if that fixes the problem.. but realize that you are guessing. and could likely be guessing wrong and wasting time and money. If i were you i would take the car to a different qualified mechanic who can diagnose the car and not simply guess and swap parts.

if you had a trouble code (CEL) then we could help you by determining the likely cause behind the cel code number, but i have not seen that, so i think the reasonable thing to do is take the car to a qualified shop to diagnose and fix the problem.
Click to expand...


Ok, here's the problem with your suggestion... I can't. Why? Because the genius's in charge of NJ made it illegal for any service station who's not a "licensed inspection station" to work on the car once it's failed inspection. And since there isn't a dealer nearby that's a licensed inspection station, I have 2 choices:

1) I bring it to a licensed service station where who the heck knows will work on it... someone who has probably never even sat in an NSX.

or

2) I can work on it myself with the help of local NSX guru's from the forum.

I'm more inclined to take #2. :)

This is the DUMBEST law ever since I'm allowed to work on it, but my dealer is not. How insane is that??? I hate so much about NJ it's pathetic.
 
wow.. do they have a limit o how much money you have to spend based on the year of your car?? i have heard some states that will pass you after you have paid x amount for your car.

OR how about taking it to a nsx dealer that isn't authorized and telling them that you need them to diagnose the problem but that due to the law they cannot fix it. you may be better off paying them to determine what is wrong and then just having the licensed inspection station replace the parts that have been diagnosed by a qualified mechanic with the correct tools to analyse the car.

i just hate this situation and would hate for you to throw money at parts only to note solve the problem.
 
I actually went to the dealer yesterday and he said "I can't touch this car". I told him I was willing to rip the sticker off just so they would... he laughed.
 
DanRC30 said:
Because the genius's in charge of NJ made it illegal for any service station who's not a "licensed inspection station" to work on the car once it's failed inspection.
Click to expand...

What a silly/stupid law! :rolleyes: If the brakes failed a test it would be more reasonable but even then...
Couldn't it be interpreted in the way that it can't be MEASURED at the same station it failed before which would allow them to solve the problem. For the official test only you just drive to another licensed inspection. :)
 
Did you confirm that the sensor wires were hooked up correctly? Beyond that, you seem to be running out of acceptable options, so I think replacing the sensors is the right thing, though I would have saved some scratch and done them myself. When I bought my '94 with almost the same number of miles, I went through and replaced over $1k in parts, including the O2 sensors. I did it for peace of mind, knowing they'll probably be good for at least 60k and many years. At some point you have to weigh the cost of replacing parts against the time you spend doing tests and trying to figure out how to diagnose things. On my newer cars I can easily hook up my scanner and read the O2 sensors, but I don't have a scope to read them on my NSX. To me, it was preventive maintenance. IMO you have a decent chance of fixing the problem with new O2s. If it doesn't fix it, at least you'll not have to worry about the sensors for a long time, and you can move on to addressing other possibilities.

If the car is not misfiring then you most likely don't have a problem with plugs, injectors, coils or ignitors. Based on your numbers, the cat is not the root cause. If the O2s don't fix the problem post back and I'll toss out another (unlikely) possibility.
 
Well, a member here helped me change the plugs tonight (much thanks!) and we tried to do the O2 sensor, but that wasn't coming out tonight. So we left it at the plugs and called it a night. Turns out there were Denso plugs in there. They were in good shape, but they're not the OEM plug. So we put the new OEM plugs in and boy what a difference!!! The car is a rocket now! And no check engine light! I also put some fuel injector cleaner in it, but I don't think that mad a difference. I'm going to drive it around for a while and then hit inspection to see what happens. Maybe I won't need the O2 sensor I just bought!!! :rolleyes:
 
Well, I took it to inspection today and it failed again, but not by much!!! Check this out:

______ Standard __________ Reading
HC: ____ 100 _______________ 107
CO: ____ .50 _______________ 37

So, I'm close! MUCH BETTER!!! I think maybe it needs to be run a little bit and I need to run the gas out so the fuel injector cleaner is out of the fuel system. I have a feeling I'm going to pass after that. Looks like I'm gonna be doing a lot of driving tomorrow to empty the tank. :)
 
Well, not anymore. I ran the gas out with the fuel inj cleaner in it, filled it with hi-test and now it failed on both again. :( I'm going to try to pull the O2 sensor and put in the new one... prob is the sensor doesn't wanna come out. Will try using the torch next as soon as I can get it on my friend's lift.
 
Unfortunately, I do need it because I have Comptech headers which relocates the sensor and the new one is not long enough. But I can cut the new one off and send it to you probably!

They're both the same? You sure?
 
DanRC30 said:
Unfortunately, I do need it because I have Comptech headers which relocates the sensor and the new one is not long enough. But I can cut the new one off and send it to you probably!

They're both the same? You sure?
Click to expand...


If you have a 91, they are exactly the same. I just replaced both of mine last summer. The OEM sensors have a different number ONLY because one of them is a couple inches longer than the other one. SAME SENSOR JUST DIFFERENT LENGHT. One is Hose A and the other is Hose B.

If you have Comptech headers you should have an extender pigtail anyway, I think, if not then the replacement sensor should just "Plug n Play". If it has an extender did you check it to see if it was connected tight? I was thinking that you had the stock exhaust manifolds installed. You didn't say anything about headers.
Don't forget to disconnect the battery (-) terminal or pull one of the fuses (I think it is the clock, check the manual) to reset the ECU. When you get all of this done.
Brad
 
Wait a second... I need to reset the system before going through inspection??? I didn't do that after swapping out the plugs! :eek:
 
DanRC30 said:
Wait a second... I need to reset the system before going through inspection??? I didn't do that after swapping out the plugs! :eek:
Click to expand...

WOOPS

Since this whole problem has started have you reset the ECU? When they did the TB/WP they had to remove the alternator and surely they disconnected the battery, but since all of the emission tests have failed and you have tried all of these different things has the battery been disconnected?
 
DanRC30 said:
Nope. :frown:
Click to expand...

Well since you haven't been able to remove the O2 sensor, is it still connected to the harness? If so, do the ECU reset, get the car warmed up real good and test it again. What do you have to loose? Do you have a OEM manual, or the on line one? I have one on my laptop and looked it up for you. Remove the CLOCK Fuse 7.5 amp from the MAIN FUSE BOX for at least 10 sec. This is from Page 6-11 in the Maintenance Manual.
Brad
 
I have the big black book.

I have a battery connector I can shut the battery off with a turn of the handle. I'll do that and try inspection again this week.

The sensor is still in without wires cut. I'm gonna have to put a torch to the headers and use a large pipe wrench to get this one out...
 
If you can get at it, the pipe wrench may be the tool for the problem. If so, I bet that you can get it out without having to put the heat to it. The new one should have anti-sieze on the threads, if not PUT SOME ON IT. Be sure to use a TORQUE wrench to install the new one.

I bet that when the headers were installed the mechanic didn't put any on the sensor threads because he probably used the old sensor. If you put the anti-sieze on the threads be VERRRRRRY careful not to get any anti-sieze on anything but the threads.
 
The comptech headers relocate the O2 sensor right behind the oil pan which is a HUGE benefit. It's almost worth getting the header just for that alone!
 

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